Earthquake Glossary - soil
Soil is (1) In engineering, all unconsolidated material above bedrock. (2) In soil science, naturally occurring layers of mineral and (or) organic constituents that differ from the underlying parent material in their physical, chemical, mineralogical, and morphological character because of pedogenic processes (3) In other words, dirt.
Soil profile in hills of Manisa Province, Turkey, showing a distinct horizon of accumulated red-purple metallic (manganese and/or iron?) oxides.